Theta Oilfield Services, Inc was founded as Theta Enterprises, Inc. in 1989 and has since become the leader in Rod Pumping Optimization software and training. Theta Oilfield Services has developed diagnostic, design, pumping unit balancing, dynamometer data measurement, and smart oilfield automation software that are used by many oil companies, service companies, and rod pumping equipment supplier. Theta Oilfield Services also provides training courses and consulting services in rod pumping optimization.

Starting Version 2015 REL 1, the functionality of XDIAG-V and XDIAG-D have been merged into one software named XDIAG. XDIAG could perform diagnostic and analysis on both vertical and deviated/horizontal wells.